title: Dual-color nanoscale assemblies of structurally stable, few-atom silver clusters, as reported by fluorescence resonance energy transfer.
abstract: We develop approaches to hold fluorescent silver clusters composed of only 10-20 atoms in nanoscale proximity, while retaining the individual structure of each cluster. This is accomplished using DNA clamp assemblies that incorporate a 10 atom silver cluster and a 15 or 16 atom silver cluster. Thermally modulated fluorescence resonance energy transfer (FRET) verifies assembly formation. Comparison to Förster theory, using measured spectral overlaps, indicates that the DNA clamps hold clusters within roughly 5 to 6 nm separations, in the range of the finest resolutions achievable on DNA scaffolds. The absence of spectral shifts in dual-cluster FRET pairs, relative to the individual clusters, shows that select few-atom silver clusters of different sizes are sufficiently stable to retain structural integrity within a single nanoscale DNA construct. The spectral stability of the cluster persists in a FRET pair with an organic dye molecule, in contrast to the blue-shifted emission of the dye.
authors.affiliation: Chemistry and Biochemistry Department and ‡Physics Department UCSB , Santa Barbara, California 93117, United States.
authors.forename: Danielle
authors.initials: D
authors.lastname: Schultz
authors.forename: Stacy M
authors.initials: SM
authors.lastname: Copp
authors.forename: Nemanja
authors.initials: N
authors.lastname: Markešević
authors.forename: Kira
authors.initials: K
authors.lastname: Gardner
authors.forename: Sumant S R
authors.initials: SS
authors.lastname: Oemrawsingh
authors.forename: Dirk
authors.initials: D
authors.lastname: Bouwmeester
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Gwinn
mesh_terms: D001483:Base Sequence; D004396:Coloring Agents / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D031541:Fluorescence Resonance Energy Transfer; D053768:Metal Nanoparticles / Q000737:chemistry; D008969:Molecular Sequence Data; D036103:Nanotechnology / Q000379:methods*; D016011:Normal Distribution; D009841:Oligonucleotides / Q000737:chemistry; D012235:Rhodamines / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013696:Temperature
chemical_list: D004396:Coloring Agents; D009841:Oligonucleotides; D012235:Rhodamines; D012834:Silver; D004247:DNA